18.4. Power Supply Board (PCB4) ------------------------175
19 Appendix Information of Schematic Diagram ------- 176
20 Exploded View and Replacement Parts List---------- 177
20.1. Cabinet and Mechanical Parts Location ----------177
20.2. Replacement Parts List -------------------------------185
2
KX-FT981LA-B / KX-FT987LA-B
1Safety Precautions
1. Before servicing, unplug the AC power cord to prevent an electric shock.
2. When replacing parts, use only the manufacturer's recommended components.
3. Check the condition of the power cord. Replace if wear or damage is evident.
4. After servicing, be sure to restore the lead dress, insulation barriers, insulation papers, shields, etc.
5. Before returning the serviced equipment to the customer, be sure to perform the following insulation resistance test to prevent
the customer from being exposed to shock hazards.
1.1.For Service Technicians
• Repair service shall be provided in accordance with repair technology information such as service manual so as to prevent fires, injury or electric shock, which can be caused by improper repair work.
1. When repair services are provided, neither the products nor their parts or members shall be remodeled.
2. If a lead wire assembly is supplied as a repair part, the lead wire assembly shall be replaced.
3. FASTON terminals shall be plugged straight in and unplugged straight.
• ICs and LSIs are vulnerable to static electricity.
When repairing, the following precautions will help prevent recurring malfunctions.
1. Cover plastic parts boxes with aluminum foil.
2. Ground the soldering irons.
3. Use a conductive mat on worktable.
4. Do not grasp IC or LSI pins with bare fingers.
1.2.AC Caution
For safety, before closing the lower cabinet, please make sure of the following precautions.
1. The earth lead is fixed with the screw.
2. The AC lead is connected properly to power supply unit.
3. Wrap the earth lead around the core 3 times.
4. Wrap the AC lead around the core 2 times.
3
KX-FT981LA-B / KX-FT987LA-B
1.3.Personal Safety Precautions
1.3.1.Moving Sections of the Unit
Be careful not to let your hair, clothes, fingers, accessories, etc., become caught in any moving sections of the unit.
The moving sections of the unit are the rollers and a gear. There is a separation roller and a document feed roller which are
rotated by the document feed motor. A gear rotates the two rollers. Be careful not to touch them with your hands, especially
when the unit is operating.
1.3.2.Live Electrical Sections
All the electrical sections of the unit supplied with AC power by the AC power cord are live.
Never disassemble the unit for service with the AC power supply plugged in.
CAUTION:
AC voltage is supplied to the primary side of the power supply unit. Therefore, always unplug the AC power cord before disassembling for service.
4
KX-FT981LA-B / KX-FT987LA-B
1.4.Service Precautions
1.4.1.Precautions to Prevent Damage from Static Electricity
Electrical charges accumulate on a person. For instance, clothes rubbing together can damage electric elements or change
their electrical characteristics. In order to prevent static electricity, touch a metallic part that is grounded to release the static
electricity. Never touch the electrical sections such as the power supply unit, etc.
5
KX-FT981LA-B / KX-FT987LA-B
2Warning
2.1.About Lead Free Solder (PbF: Pb free)
Note:
In the information below, Pb, the symbol for lead in the periodic table of elements, will refer to standard solder or solder that contains lead.
We will use PbF solder when discussing the lead free solder used in our manufacturing process which is made from Tin, (Sn),
Silver, (Ag), and Copper, (Cu).
This model, and others like it, manufactured using lead free solder will have PbF stamped on the PCB. For service and repair
work we suggest using the same type of solder although, with some precautions, standard Pb solder can also be used.
Caution
PbF solder has a melting point that is 50° ~ 70° F, ( 30° ~ 40°C) higher than Pb solder. Please use a soldering iron with temperature
control and adjust it to 700° ± 20° F, (3 7 0° ± 10°C). In case of using high temperature soldering iron, please be careful not to heat
too long.
PbF solder will tend to splash if it is heated much higher than its melting point, approximately 1100°F, (6 00 °C).
If you must use Pb solder on a PCB manufactured using PbF solder, remove as much of the original PbF solder as possible and be
sure that any remaining is melted prior to applying the Pb solder.
When applying PbF solder to double layered boards, please check the component side for excess which may flow onto the opposite
side (See figure, below).
2.1.1.Suggested PBF Solder
There are several types of PbF solder available commercially. While this product is manufactured using Tin, Silver, and Copper,
(Sn+Ag+Cu), you can also use Tin and Copper, (Sn+Cu), or Tin, Zinc, and Bismuth, (Sn+Zn+Bi). Please check the manufacturer’s specific instructions for the melting points of their products and any precautions for using their product with other
materials.
The following lead free (PbF) solder wire sizes are recommended for service of this product: 0.3mm, 0.6mm and 1.0mm.
6
KX-FT981LA-B / KX-FT987LA-B
2.2.Insulation Resistance Test
1. Unplug the power cord and short the two prongs of the plug with a jumper wire.
2. Turn on the power switch.
3. Measure the resistance value with an ohmmeter between the jumpered AC plug and each exposed metal cabinet part
(screw heads, control shafts, bottom frame, etc.).
Note: Some exposed parts may be isolated from the chassis by design. These will read infinity.
4. If the measurement is outside the specified limits, there is a possibility of a shock hazard.
2.3.Battery Caution
CAUTION
Danger of explosion if the battery is incorrectly replaced. Replace only with the same or equivalent type recommended by the
manufacturer. Dispose of used batteries according to the manufacturer’s Instructions.
The lithium battery is a critical component (type No. CR2032). Please observe for the proper polarity and the exact location
when replacing it and soldering the replacement lithium battery in.
2.4.Discarding of P. C. Board
When discarding P. C. Board, delete all personal information such as telephone directory and caller list or scrap P. C. Board.
Dimensions (H×W×D):Approx. height 121 mm × width 352 mm × depth 224 mm
Mass (Weight):KX-FT981: Approx. 2.7 kg
KX-FT987: Approx. 2.8 kg
Power Consumption:Standby: Approx. 1.2 W (KX-FT981)
Standby: Approx. 1.4 W (KX-FT987)
Transmission: Approx. 13 W
Reception: Approx. 30 W (When receiving a 20% black document)
Copy: Approx. 35 W (When copying a 20% black document)
Maximum: Approx. 120 W (When copying a 100% black document)
Power Supply:120 V AC, 60 Hz
Fax Memory Capacity
*3
:
Approx. 28 pages of memory reception
(Based on the ITU-T No. 1 Test Chart in standard resolution, with original mode.)
Voice Memory Capacity
(KX-FT987 only):
*4
Approx. 12 minutes of recording time including greeting message when no documents are
in memory.
*2
*1
Transmission speed depends upon the contents of the pages, resolution, telephone line conditions and capability of the other
party’s machine.
*2
Transmission speed is based upon the ITU-T No. 1 Test Chart with original mode. If the capability of the other party’s machine is
inferior to your unit, the transmission time may be longer.
*3
If an error occurs during fax reception, such as a paper jam or if the recording paper runs out, the fax and subsequent faxes will
be retained in memory.
*4
Recording time may be reduced by the calling party’s background noise.
Note:
Design and specifications are subject to change without notice.
8
KX-FT981LA-B / KX-FT987LA-B
4General/Introduction
4.1.Optional Accessories
Model No.ItemSpecifications/Usage
1
KX-A106
*1
Use only the included or specified recording paper. Using other recording paper may affect print quality and/or cause exces-
sive wear to the thermal head.
Standard thermal recording paper*
4.2.Translation Lists
4.2.1.Error Messages-Display
216 mm × 30 m roll, with 25 mm core
9
KX-FT981LA-B / KX-FT987LA-B
4.2.2.Error Messages-Report
4.2.3.Other-Display
5Features
General
• LCD (Liquid Crystal Display) readout
• The display and reports will be in the selected language.
(Spanish / Portuguese / English)
• Automatic Paper Cutter (KX-FT987 only)
Facsimile
• Document memory
• Automatic document feeder (10 sheets)
• 64-Level halftone resolution
Standard/Fine/Photo/Super Fine
• Broadcast
Integrated Telephone System
• Phonebook function (100 names)
• One-Touch Dial (10 stations)
• Caller ID compatible
• Monitor (KX-FT981 only)
• Digital SP-Phone (KX-FT987 only)
Digital Answering System (KX-FT987 only)
• Voice Time/Day Stamp
• 12-Minutes recording time
10
6Technical Descriptions
6.1.Connection Diagram
KX-FT981LA-B / KX-FT987LA-B
11
KX-FT981LA-B / KX-FT987LA-B
6.2.General Block
The following is an outline of each device IC on the digital board. (Refer to General Block Diagram (P.13).).
1. ASIC (IC1)
Composed mainly of an address decoder and a modem control.
Controls the general FAX operations.
Controls the operation panel I/F.
Controls the thermal head I/F and CIS I/F.
Performs the image processing.
CPU and Real time clock
Provides the reset pulse for each of the major ICs.
2. Flash ROM (IC2)
Contains all of the program instructions on the unit operations.
This memory is used mainly for the parameter working in the storage area.
3. Dynamic RAM (IC4)
This memory is used mainly for the parameter working in the storage area.
4. MODEM (IC5)
Performs the modulation and the demodulation for FAX communication.
5. Read Section
CIS image sensor to read transmitted documents.
6. Motor Driver (IC7)
Drives the transmission motor and the reception motor.
7. Thermal Head
Contains heat-emitting elements for dot matrix image printing.
8. Sensor Section
Composed of a cover open, a document set switch, a document top switch, a paper sensor switch, a jam sensor switch, and
a hook sensor switch.
This custom IC is used for the general FAX operations.
1. CPU:
This model uses a Z80 equivalent to the CPU operating
at 24 MHz. Most of the peripheral functions are performed
by custom-designed LSIs. Therefore, the CPU only works
for processing the results.
2. RTC:
Real Time Clock
3. DECODER:
Decodes the address.
4. ROM/RAM I/F:
Controls the SELECT signal of ROM or RAM and the
bank switching.
5. CIS I/F:
Controls the document reading.
Note:
This memory is incorporated into the ASIC (IC1) and used for the image processing.
6. IMAGE DATA RAM:
This memory is programmed into the ASIC and uses 8
KB for the image processing.
7. THERMAL HEAD I/F:
Transmits the recorded data to the thermal head.
8. MOTOR I/F:
Controls the transmission motor which feeds the document.
Controls the receiving motor which feeds the recording
paper.
9. OPERATION PANEL I/F:
Serial interface with Operation Panel.
10. I/O PORT:
I/O Port Interface.
11. ANALOG UNIT:
Electronic volume for the monitor.
Sends beep tones, etc.
Descriptions of Pin Distribution (IC1)
NO.SIGNALI/OPOWER SUPPLIED
1VSSA1GNDPOWER SOURCE (ANALOG GND)
2VDDA 3.33.3VPOWER SOURCE (ANALOG +3.3V)
3AIN1A3.3VCIS IMAGE SIGNAL INPUT (ATN1)
4AIN2A3.3VTHERMISTOR TEMPERATURE WATCH INPUT
5AIN3A3.3VLINE VOLTAGE DETECTION SIGNAL INPUT (DCIN)
6AMONA3.3VANALOG SIGNAL MONITOR TERMINAL
7VSS1GNDPOWER SOURCE (GND)
8X32OUTO3.3V/BATTRTC (32.768KHz) CONNECTION
9X32INI3.3V/BATTRTC (32.768KHz) CONNECTION
10VDD (3.3V / B)-----POWER SOURCE (+3.3V/LITHIUM BATTERY)
11XBACKENI3.3V/BATTBACKUP ENABLE
12XRAMCSO3.3V/BATTXRAMCS
13VDD (3.3V / B)-----POWER SOURCE(+3.3V / LITHIUM BATTERY)
14VDD (2.5V/B)-----POWER SOURCE (+2.5V / LITHIUM BATTERY)
15FTGO3.3VSH SIGNAL OUTPUT FOR CIS (FTG)
16F1O3.3V01 SIGNAL OUTPUT FOR CIS (F1)
17F2/OPO3.3VOUTPUT PORT (HEADON)
18FR/OPO3.3VOUTPUT PORT (MDMRST)
19CPCI3.3VINPUT PORT (BELL/CPC)
20RVNI3.3VINPUT PORT (PAPER)
21IRDATXDI3.3VINPUT PORT (JAM)
22IRDARXDO3.3VOUTPUT PORT (HSTX MUTE)
23TXD/IOPI3.3VTXD
24RXD/IOPI/O3.3VRXD
25RTS/IOPI3.3VRTS
26CTS/IOPI/O3.3VCTS
27VDD (2.5V)1-----POWER SOURCE (+2.5V)
28TONE1A3.3VTONE OUTPUT
29TONE2A3.3VTONE OUTPUT
30VOLUREF/VOLU1A3.3VANALOG REF VOLTAGE
31VOLUOUT/VOLU2A3.3VVOLUME OUTPUT
32VOLUIN/VOLU3A3.3VVOLUME INPUT
33XNMII3.3VHIGH FIXED
34FMEMDO/IOPO3.3VOUTPUT PORT (LED ON)
35VDD (3.3V)1-----POWER SOURCE (+3.3V)
36VSS2GNDPOWER SOURCE (GND)
37VSS3GNDPOWER SOURCE (GND)
DESCRIPTION
VOLTAGE
14
KX-FT981LA-B / KX-FT987LA-B
NO.SIGNALI/OPOWER SUPPLIED
DESCRIPTION
VOLTAGE
38VDD (3.3V)2-----POWER SOURCE (+3.3V)
39MIDAT/IOPI/O3.3VPORT (TONE1EN)
40MICLK/IOPO3.3VOUTPUT PORT (MDMTXEN)
41MILAT/IOPI/O3.3VPORT (HSRXEN)
4220KOSC/IOPO3.3VOUTPUT PORT (PSHORT/ACK_EN)
43XWAITI3.3VINPUT PORT (HOOK)
44XHSTRD/IOPI3.3VINPUT PORT (TEST)
45XHSTWR/IOPO3.3VOUTPUT PORT (DCN)
46XOPRBEO 3.3VOUTPUT PORT (MFCS)
47ADR15O3.3VCPU ADDRESS BUS 15 (NOT USED)
48ADR14O3.3VCPU ADDRESS BUS 14 (NOT USED)
49ADR13O3.3VCPU ADDRESS BUS 13 (NOT USED)
50VDD (2.5V)2-----POWER SOURCE (+2.5V)
51XOUTO3.3VSYSTEM CLOCK (24MHz)
52XINI3.3VSYSTEM CLOCK (24MHz)
53VSS4GNDPOWER SOURCE (GND)
54VDD (3.3V)3-----POWER SOURCE (+3.3V)
55XTESTO3.3V24MHz CLOCK
56TEST1I3.3VHIGH FIXED
57TEST2I3.3VHIGH FIXED
58TEST3I3.3VHIGH FIXED
59TEST4I3.3VHIGH FIXED
60XMDMINTI3.3VMODEM INTERRUPT
61XMDMCSO3.3VMODEM CHIP SELECT
62XRAS/IOPO3.3VDRAM ROW ADDRESS STROBE (RAS)
63XCAS1/IOPO3.3VDRAM COLUMN ADDRESS STROBE (CAS)
64XCAS2/IOPI3.3VPORT (SPMUTE)
65XRESCS2O3.3VFLASH CHIP SELECT (XRESCS2)
66DB3I/O3.3VCPU DATA BUS 3
67DB2I/O3.3VCPU DATA BUS 2
68DB4I/O3.3VCPU DATA BUS 4
69DB1I/O3.3VCPU DATA BUS 1
70DB5I/O3.3VCPU DATA BUS 5
71VDD (3.3V)4-----POWER SOURCE (+3.3V)
72VSS5GNDPOWER SOURCE (GND)
73VSS6GNDPOWER SOURCE (GND)
74VDD (3.3V)5-----POWER SOURCE (+3.3V)
75DB0I/O3.3VCPU DATA BUS 0
76DB6I/O3.3VCPU DATA BUS 6
77DB7I/O3.3VCPU DATA BUS 7
78XROMCSO 3.3VFLASH (IC2) CHIP SELECT
79XRDO 3.3VCPU RD
80XWRO 3.3VCPU WR
81ADR0O 3.3VCPU ADDRESS BUS 0
82ADR1O 3.3VCPU ADDRESS BUS 1
83ADR2O 3.3VCPU ADDRESS BUS 2
84ADR3O3.3VCPU ADDRESS BUS 3
85ADR4O 3.3VCPU ADDRESS BUS 4
86ADR5O 3.3VCPU ADDRESS BUS 5
87VSS7GNDPOWER SOURCE (GND)
88VDD (2.5V)3-----POWER SOURCE (+2.5V)
89ADR6O3.3VCPU ADDRESS BUS 6
90ADR7O3.3VCPU ADDRESS BUS 7
91ADR8O3.3VCPU ADDRESS BUS 8
92ADR9O3.3VCPU ADDRESS 9
93ADR10O3.3VCPU ADDRESS 10
94ADR11O3.3VCPU ADDRESS 11
95ADR12O3.3VCPU ADDRESS 12
96RBA0O3.3VROM/RAM BANK ADDRESS 0
97RBA1O3.3VROM/RAM BANK ADDRESS 1
98RBA2O3.3VROM/RAM BANK ADDRESS 2
99RBA3O3.3VROM/RAM BANK ADDRESS 3
100RBA4O3.3VROM/RAM BANK ADDRESS 4
101RBA5O3.3VROM/RAM BANK ADDRESS 5
102RBA6/IOPO3.3VOUTPUT PORT (NC)
103STB1O3.3VSTROBE SIGNAL OUTPUT TO THERMAL HEAD
15
KX-FT981LA-B / KX-FT987LA-B
NO.SIGNALI/OPOWER SUPPLIED
VOLTAGE
104STB2O3.3VSTROBE SIGNAL OUTPUT TO THERMAL HEAD
105STB3O3.3VOUTPUT PORT (NC)
106XRESETI3.3VRESET INPUT
107VDD (3.3V)6-----POWER SOURCE (+3.3V)
108VSS8GNDPOWER SOURCE (GND)
109VSS9GNDPOWER SOURCE (GND)
110VDD (3.3V)7-----POWER SOURCE (+3.3V)
111XORESETO3.3VNOT USED
112VDD(5V)-----POWER SOURCE (+5V)
113VSS10GNDPOWER SOURCE (GND)
114XRESETII3.3VRESET INPUT
115XWDERRO3.3VWATCHED ERROR OUTPUT SIGNAL
116THDATO3.3VRECORDED IMAGE OUTPUT (THDAT)
117THCLKO3.3VCLOCK OUTPUT FOR DATA TRANSFER (THCLK)
118THLATO3.3VPULSE OUTPUT FOR DATA LATCH (THLAT)
119STBNPI3.3VINPUT PORT (MOT-POS)
120RM0/IOPO3.3VMOTOR A PHASE
121RM1/IOPO3.3VMOTOR B PHASE
122RM2/IOPO3.3VMOTOR /A PHASE
123RM3/IOPO3.3VMOTOR /B PHASE
124RXE/IOPO3.3VMOTOR ENABLE
125TMOO3.3VOUTPUT PORT (R1)
126VDD (2.5V)4-----POWER SOURCE (+2.5V)
127VSS11GNDPOWER SOURCE (GND)
128TM1/IOPO3.3VOUTPUT PORT (R2)
129TM2/IOPO3.3VOUTPUT PORT (CISON)
130TM3/IOPO3.3VOUTPUT PORT (RLY)
131TXE/IOPI3.3VINPUT PORT (CUT_POS)
132KSTARTO3.3VOPERATION PANEL CONTROL
133KLATCHO3.3VOPERATION PANEL CONTROL
134KSCLKO3.3VOPERATION PANEL CONTROL
135KTXDO3.3VOPERATION PANEL CONTROL
136KRXDI3.3VOPERATION PANEL CONTROL
137FMEMCLK/IOPO3.3VOUTPUT PORT (OPRESET)
138FMEMDI/IOPO3.3VOUTPUT PORT (NC)
139ADSEL1O3.3VCHANNEL SELECT SIGNAL FOR AIN2
140VDDA (2.5V)2.5VPOWER SOURCE (ANALOG +2.5V)
141VREFBA3.3VA/D CONVERTER'S ZERO STANDARD VOLTAGE
OUTPUT
142VCLA3.3VANALOG PART STANDARD VOLTAGE SIGNAL
143VREFTA3.3VA/D CONVERTER'S FULL SCALE VOLTAGE OUTPUT
144VSSA2GNDPOWER SOURCE (ANALOG GND)
DESCRIPTION
Connection to operation reset circuit
16
KX-FT981LA-B / KX-FT987LA-B
6.3.2.Flash Memory (IC2)
This 512KB ROM (FLASH MEMORY) carries a common area of 32KB and bank areas which each have 8KB (BK4~BK63). The
addresses from 0000H to 7FFFH are for the common area and from 8000H to 9FFFH are for the bank areas.
6.3.3.Dynamic RAM (IC4)
The DRAM serves as CPU and receives memory.
The address is F200H~F3FFH (DRAM access window 1) and F600H~F7FFH (DRAM access window 2).
6.3.4.Reset Circuit (Watch dog timer)
The output signal (reset) from pin 4 of the voltage detect IC (IC3) is input to the ASIC (IC1) 114 pin.
1. During a momentary power interruption, a positive reset pulse of 50~70 msec is generated and the system is reset completely.
2. The watch dog timer, built-in the ASIC (IC1), is initialized by the CPU about every 1.5 ms.
When a watch dog error occurs, pin 115 of the ASIC (IC1) becomes low level.
The terminal of the 'WDERR' signal is connected to the reset line, so the 'WDERR' signal works as the reset signal.
17
KX-FT981LA-B / KX-FT987LA-B
6.3.5.RTC Back up Circuit
1. Function
This unit has a lithium battery (BAT1) which works for the Real Time Clock (RTC, Integrated into ASIC:IC1).
The RTC continues functioning, even when the power switch is OFF, backed up by a lithium battery.
2. Circuit Operation
When the power is turned ON, power is supplied to RTC (IC1).
At this time, the voltage at pin 14 of RTC (IC1) is +3.3V. When the power is turned OFF, the battery supplies the power to RTC
through JS1, R30, D14. At that time, the voltage at pin 14 of IC1 are about +2.5V. When the power is OFF and the +5V and
+3.3V voltages decrease, the LOW is input to pin 114 of IC1. Pin 111 of IC1 outputs the reset signals. Pin 11 of IC1 become
low, then RTC (IC1) go into the back up mode, when the power consumption is lower.
18
KX-FT981LA-B / KX-FT987LA-B
6.3.6.Supervision Circuit for the Thermal Head Temperature
1. Function
The thermistor changes the resistor according to the temperature and uses the thermistor's characteristics. The output of pin
139 of IC1 becomes a low level. Then when it becomes a high level, it triggers point A. In point C, according to the voltage
output time, the thermal head's temperature is detected.
After the thermal head temperature is converted to voltage in B, it is then changed to digital data in the A/D converter inside
IC1. The CPU decides the strobe width of the thermal head according to this value. Therefore, this circuit can keep the thermal head at an even temperature in order to stabilize the printing density and prevent the head from being overheated.
REFERENCE:
Thermal Head (P.22)
19
KX-FT981LA-B / KX-FT987LA-B
6.4.Facsimile Section
6.4.1.Image Data Flow During Facsimile Operation
Copy (Fine, Super-Fine, Photo)
1. Line information is read by CIS (to be used as the reference white level) via route (1), and is input to IC1. Refer to Block Diagram (P.21)
2. In IC1, the data is adjusted to a suitable level for A/D conversion in the Analog Signal Processing Section, and via route (2) it
is input to A/D conversion (8 bit). After finishing A/D conversion, the data is input to the Image Processing Section via route
(3). Then via route (4) and route (5), it is stored in RAM as shading data.
3. The draft’s information that is read by CIS is input to IC1 via route (1). After it is adjusted to a suitable level for A/D conversion
via route (2), the draft’s information is converted to A/D (8 bit), and it is input to the Image Processing Section. The other side,
the shading data which flows from RAM via route (6) and route (7), is input to the Image Processing Section. After finishing
the draft’s information image processing, white is regarded as "0" and black is regarded as "1". Then via routes (4) and (5),
they are stored in RAM.
4. The white/black data stored as above via routes (6) and (8) is input to the P/S converter. The white/black data converted to
serial data in the P/S converter is input to the Thermal Head via route (9) and is printed out on recording paper.
2. The data stored in the RAM of IC1 is output from IC1 via routes (6) and (10), and is stored in the system bus.
Via route (11), it is stored in the communication buffer inside DRAM (IC4).
3. While retrieving data stored in the communication buffer synchronous with the modem, the CPU (inside IC1) inputs the data to
the modem along route (12), where it is converted to serial analogue data and forwarded over the telephone lines via the
NCU Section.
Reception
1. The serial analog image data is received over the telephone lines and input to the modem via the NCU section, where it is
demodulated to parallel digital data. Then the CPU (IC1) stores the data in the communication buffer DRAM (IC4) along route
(11).
2. The data stored in DRAM (IC4) is decoded by the CPU (IC1) via route (12), and is stored in RAM via routes (13) and (5).
3. Same processing as Copy item 4.
20
6.4.2.Block Diagram
KX-FT981LA-B / KX-FT987LA-B
21
KX-FT981LA-B / KX-FT987LA-B
6.4.3.Thermal Head
1. Function
This unit utilizes state of the art thermal printer technology.
The recording paper (roll paper) is chemically processed. When the thermal head contacts this paper it emits heat momentarily, and black dots (appearing like points) are printed on the paper. If this continues, letters and/or diagrams appear, and the
original document is reproduced.
2. Circuit Operation
There are 27 driver ICs aligned horizontally on the thermal head and each one of these ICs can drive 64 heat emitting registers. This means that one line is at a density of 64×27=1728 dots=(8 dots/mm).
White/Black (white=0, black=1) data in one line increments is synchronized at IC1 pin 117 (THCLK), and sent from IC1 pin 116
(THDAT) to the shift register of the ICs. The shift registers of the 27 ICs are connected in series, and upon the shift of dot
increment 1728, all the shift registers become filled with data, and a latch pulse is emitted to each IC from IC1 pin 118
(THLAT).With this latch pulse, all the contents of the shift registers are latched to the latch registers. Thereafter, through the
addition of strobes from the IC1 pins (103 - 104) only black dot locations (=1) among latched data activates the driver, and the
current passes to heat the emitting body causing heat emission.
Here, the two line strobes, STB1 and STB2, impress at intervals of 9.216 msec, as required for one-line printout.
The sequence is shown on the next page. [Moreover, for the strobe width, the thermistor value inside the thermal head is
detected according to IC1 pin 4. Depending on that value, the strobe width is recorded in FLASH (IC2).
Accordingly, the strobe width is determined.
When the thermal head is not used, the IC1 (17, HEADON) becomes low, Q6 turns OFF, Q7 turns OFF, and the +24 V power
supply for the thermal head driver is not impressed to protect the IC.
22
KX-FT981LA-B / KX-FT987LA-B
23
KX-FT981LA-B / KX-FT987LA-B
6.4.4.Scanning Block
The scanning block of this device consists of a control circuit and a contact image sensor made up of a celfoc lens array, a light
source, and photoelectric conversion elements.
When an original document is inserted and the start button pressed, pin 129 of IC1 goes to a low level and the transistor Q14 turns
on.This applies voltage to the light source to light it. The contact image sensor is driven by each of the FTG-F1 signals output from
IC1, and the original image illuminated by the light source undergoes photoelectric conversion to output an analogue image signal
(AIN). The analogue image signal is input to the system ASIC on AIN1 (pin 3 of IC1) and converted into 8-bit data by the A/D converter inside IC1. Then this signal undergoes digital processing in order to obtain a high-quality image.
24
KX-FT981LA-B / KX-FT987LA-B
6.4.5.Stepping Motor Drive Circuit
1. Function
One individual stepping motor is used for transmission and reception. It feeds the document or recording paper synchronized
for reading or printing.
2. Circuit Operation
During motor drive, ASIC IC1 pin 124 becomes a high level, and Q2 and Q1 go ON as a result. +24 V is supplied tothe motor
coil.
Stepping pulses are output from ASIC IC1, causing driver IC7 to go ON. The motor coil is energized sequentially in 2 phase
increments or 1-2 phase increments, which causes a 1-step rotation. A 1-step rotation is 0.13mm of recording paper or document paper. The timing chart is below.
Stepping Motor Phase Pattern
FunctionModePhase PatternSpeed
CopyFine/Photo1-2432 pps
Super Fine1-2216 pps
FAXSTD2432 pps
Fine/Photo1-2432 pps
Super Fine1-2216 pps
———Paper Feed2432 pps
When the motor is OFF, ASIC IC1 pin 124 becomes a low level and Q2 and Q1 also turns OFF. Instead of +24V, +5V is supplied
through D11 so that the motor is held in place.
25
KX-FT981LA-B / KX-FT987LA-B
6.5.Sensors and Switches
All of the sensors and switches are shown below.
Sensor Circuit
Location
DIGITALCN5Motor Position Sensor[CALL SERVICE]
ANALOGSW101Cover Open / Paper Sensor [COVER OPEN] and [CHECK PAPER]
Operation PanelSW338Document Top Sensor[REMOVE DOCUMENT]
SensorSensor or Switch NameError Message (*1)
CN6 Cutter Position Sensor
SW102Hook Sensor————
SW103JAM Sensor[PAPER JAMED]
SW339Document Set Sensor[CHECK DOCUMENT]
Note:
• SEE Test Mode (P.54) for Sensor Check (#815).
• (*1) Refer to Translation Lists (P.9) for display.
[PAPER JAMED]
(KX-FT987 only)
26
6.5.1.Motor Position Sensor
This sensor is a detection switch for recording the position of the CAM.
Signal (IC1-119 pin)
Home positionLow level
OtherHigh level
6.5.2.Cutter Position Sensor (KX-FT987 only)
KX-FT981LA-B / KX-FT987LA-B
Signal (IC1-131 pin)
Home positionLow level
OtherHigh level
6.5.3.Cover Open / Paper Sensor (SW101)
When the recording paper is loaded on the print head and the cover is closed, the paper sensor SW turns ON, and the input signal
of IC1-20 pin becomes a low level. Usually, the SW turns OFF, and the input signal of IC1-20 pin becomes a high level.
SensorSignal (IC1-20 pin)
Set recording paper and cover is closedONLow level
No recording paper or cover is openOFFHigh level
27
KX-FT981LA-B / KX-FT987LA-B
6.5.4.Hook Sensor (SW102)
When the handset is lifted, the switch turns ON, and the signal at pin 43 of IC1 becomes low.
When the handset is returned, the switch turns OFF, and the signal at pin 43 of IC1 becomes high.
The JAM sensor is a detection switch for determining whether the recording paper edge is in the correct position or not. If the
recording paper cannot be detected correctly at the JAM sensor position even when recording paper is present, then JAM is displayed. If the recording paper is at the sensor position, then the switch turns on the IC1-21 pin switches to a high level.
Signal (IC1-21 pin)
PaperLow level
No paperHigh level
28
KX-FT981LA-B / KX-FT987LA-B
6.5.6.Document Top Sensor (SW338)
When a document is brought to the read position, the SW becomes ON, and the input signal of IC301-5 pin (Operation Board)
becomes a low level. When there is no document at the read position, the SW becomes OFF, and the input signal of IC301-5 pin
(Operation Board) becomes a high level.
Sensor SWSignal (IC301-5 pin)
Out of the Read PositionOFFHigh level
At the Read PositionONLow level
6.5.7.Document Set Sensor (SW339)
When a document is set, the SW becomes ON, and input signal of IC301-6 pin (Operation Board) becomes a low level.
When there is no document, the SW becomes OFF, and the input signal of IC301-6 pin (Operation Board) becomes a high level.
Sensor SWSignal (IC301-6 pin)
No documentOFFHigh level
Set documentONLow level
29
KX-FT981LA-B / KX-FT987LA-B
6.6.Modem Section
6.6.1.Function
The unit uses a 1 chip modem (IC5) that serves as an interface between the control section for FAX transmission and reception
and the telephone line. During a transmitting operation, the digital image signals are modulated and sent to the telephone line.
During a receiving operation, the analogue image signals which are received via the telephone line are demodulated and converted into digital image signals. The communication format and procedures for FAX communication are standardized by ITU-T.
This 1 chip modem (IC5) has hardware which sends and detects all of the necessary signals for FAX communication (DTMF).
It can be controlled by writing commands from the CPU (IC1: inside ASIC) to the register in the modem (IC5).
This modem (IC5) also sends DTMF signals, generates a call tone (from the speaker), and detects a busy tone and dial tones.
Overview of Facsimile Communication Procedures (ITU-T Recommendation):
1. ON CCITT (International Telegraph and Telephone Consultative Committee)
The No. XIV Group of CCITT, one of the four permanent organizations of the International Telecommunications Union (ITU),
investigates and make recommendations on international standards for facsimiles.
2. Definition of Each Group
• Group I (G1)
Official A-4 size documents without using formats which reduce the band width of a signal are sent over telephone lines.Determined in 1968.
Transmission for about 6 minutes at a scanning line density of 3.85 lines/mm.
• Group II (G2)
Using reduction technology in the modulation/demodulation format, an A-4 size document is sent at an official scanning line density of 3.85 lines/mm for about 3 minutes.
Methods to suppress redundancy are not used.
Determined in 1976.
• Group III (G3)
Method of suppressing redundancy in the image signal prior to modulation is used. An A-4 size document is sent within about
one minute.
Determined in 1980.
• Group IV (G4)
Transmission is via the data network. A method is provided for suppressing redundancy in signals prior to transmission, and
error-free reception of transmission is possible.
The scope of these facsimile applications is not limited simply to transmission of written statements. Through symbiotic linkages
with other communication methods, it can be expected to expand to include integrated services.
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